<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Border-Test</title>
    <style>
        body {
            width: 100%;
            height: 100%;
            background: #F5F5F5;
        }
        #app {
            display: flex;
            flex-direction: column;
            /* width:  100%; */
            padding: 3%;
        }
        .row {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            margin: 10px;
            border: 4px solid #FFFFFF;
        }
        .row>div {
            background-color: rgba(0, 0, 0, 0.8);
        }
        .border1 {
            width: 50px;
            height: 50px;
            border: 2px solid;
            border-color: brown blueviolet chocolate royalblue;
        }
        .border2 {
            width: 50px;
            height: 50px;
            border: 50px solid;
            border-color: brown blueviolet chocolate royalblue;
        }
        .border3 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: brown blueviolet chocolate royalblue;
        }
        .border4 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: brown transparent transparent transparent;
        }
        .border5 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent blueviolet transparent transparent;
        }
        .border6 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent transparent chocolate transparent;
        }
        .border7 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent transparent transparent royalblue;
        }
        .border8 {
            width: 0;
            height: 0;
            border-style: solid;
            border-width: 0 50px 50px 50px;
            border-color: transparent transparent forestgreen transparent;
        }
        .border9 {
            width: 0;
            height: 0;
            border-style: solid;
            border-width: 50px 0 50px 50px;
            border-color: transparent transparent transparent forestgreen;
        }
        .border10 {
            width: 0;
            height: 0;
            border-style: solid;
            border-width: 50px 50px 0 50px;
            border-color: forestgreen transparent transparent transparent;
        }
        .border11 {
            width: 0;
            height: 0;
            border-style: solid;
            border-width: 50px 50px 50px 0;
            border-color: transparent forestgreen transparent transparent;
        }
        .border12 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent tomato;
        }
        .border13 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: tomato transparent;
        }
        .border14 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent tomato transparent transparent;
            position: relative;
        }
        .border14::after {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent transparent transparent seagreen;
            position: absolute;
            content: ' ';
            top: -50px;
            left: 50px;
        }
        .border15 {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: transparent transparent tomato transparent;
            position: relative;
        }
        .border15::before {
            width: 0;
            height: 0;
            border: 50px solid;
            border-color: seagreen transparent transparent transparent;
            position: absolute;
            content: ' ';
            top: 0;
            right: 0;
        }
        .border16 {
            width: 0;
            height: 0;
            border-style: solid;
            border-width: 0 50px 50px;
            border-color: transparent transparent darkcyan;
            position: relative;
        }
        .border16::after {
            content: ' ';
            position: absolute;
            top: 0;
            left: 0;
            border-style: solid;
            border-width: 0 50px 50px;
            border-color: transparent transparent darkorange;
        }
        .border17 {
            width: 0;
            height: 0;
            border-style: solid;
            border-width: 0 50px 50px;
            border-color: transparent transparent darkcyan;
            position: relative;
        }
        .border17::after {
            content: ' ';
            position: absolute;
            top: 6px;
            left: -40px;
            border-style: solid;
            border-width: 0 40px 40px;
            border-color: transparent transparent darkorange;
        }
        .box {
            /* 内部大小 */
            width: 0px;
            height: 0px;
            /* 边框大小 只设置两条边*/
            border-top: #4285f4 solid;
            border-right: transparent solid;
            border-width: 85px; 
            /* 其他设置 */
            margin: 50px;
        }
    </style>
</head>
<body>
    <div id="app">
        <div class="row">
            <div class="border1"></div>
            <div class="border2"></div>
            <div class="border3"></div>
        </div>
        <div class="row">
            <div class="border4"></div>
            <div class="border5"></div>
            <div class="border6"></div>
            <div class="border7"></div>
        </div>
        <div class="row">
            <div class="border8"></div>
            <div class="border9"></div>
            <div class="border10"></div>
            <div class="border11"></div>
        </div>
        <div class="row">
            <div class="border12"></div>
            <div class="border13"></div>
            <div class="border14"></div>
            <div class="border15"></div>
        </div>
        <div class="row">
            <div class="border16"></div>
            <div class="border17"></div>
        </div>
        <div class="row">
            <div class="box"></div>
        </div>
    </div>
</body>
</html>